The on-going deregulation in worldwide energy distribution markets is driving the need for smart utility distribution grids and smart meters, enabling both utility providers and consumers to monitor the detailed consumption of an end user at any time through open communication networks or unreliable networks such as internet. The energy market is particularly concerned as of today but related issues are also relevant to other utility markets such as water or gas.
Automated meters enable utility providers to remotely read the meter registers that record on a regular basis the user consumption information. However, this reading only occurs from time to time at the discretion of the utility provider and typically uses a private network (wireless or cable) under close control by the utility provider. The next generation of automated meters (so called smart meters) will enable utility providers, such as remote utility management center, to monitor the detailed consumption of an end user at any time and at a much finer granularity through open communication networks. This finer grain monitoring is expected to encourage more precisely targeted rates and offerings to the end user, possibly by competing utility providers, as the utility markets get deregulated similar to the telecommunications markets in the 90s. It will become even more relevant when HAN (Home Appliances Networks) are interconnected with the smart grid to directly report on their end usage information rather than concentrating this information reporting through the smart meter.
The utility provider can also remotely manage, configure and upgrade the meter through the communication network. In certain markets, smart meters are even required to implement a remote disconnect feature, so that the utility can remotely stop the service distribution for instance in the case of non-payment.
Consequently, a smart meter typically generates, or passes through in the HAN interconnection case, automated reading messages upstream to the remote utility provider management equipment at a much more frequent rate than former automated meters did. Those messages also possibly carry significantly longer payload as more details are monitored by the utility provider.
Clearly, the resulting dependency of the utility service and billing functionality on remote communication messages raises new concerns on data privacy and confidentiality as well the effective system robustness to software bugs and emerging threats such as smart grid worms and viruses taking advantage of smart meter security design flaws. Those flaws may not be known at the time of deployment, but may become critical later. This is particularly evident in the case of the remote disconnect feature, as a major disruption target for cyber-terrorism but also a possible entry point for local thieves as a way to disconnect some house alarms from their power source.
In practice, today's security designs for smart grids and smart meters are largely inspired by the telecommunication industry and a large part of them is subject to emerging standardization by international committees such as ANSI or IEC. Sensitive messages need to be protected by a secure authenticated channel to be established using cryptographic protocols over an individual point-to-point communication between the utility meter and the remote utility provider management equipment. Therefore, recent standard specifications in that area, such as ANSI C12.22 or IEC 62056/COSEM, define how to encrypt and sign the message payloads, typically by means of a session key setup between the utility management center or data collection concentrator and the utility meter.
As described in the “OpenWay by Itron Security Overview” White Paper from Itron, for practical, operational reasons, some of the downstream messages from the utility management center or collector concentrator may be broadcast or multicast into the utility grid network without a secure receipt acknowledgement from each target utility meter, typically because of the overhead in managing the corresponding upstream messages in a large scale metering deployment (for instance 10 million meters). However the individual meter utility usage consumption information, such as actual utility usage or event logs, have to be communicated back point-to-point from the utility meter to the utility management center or collector concentrator. Therefore, to scale their smart metering system to support up to 10 million meters, Itron reports the need for processing up to 24000 messages per second upstream, while broadcast/multicast downstream messaging enables to factorize the messages down to 200 per second.
In practice, the scalability issue will become even more critical as the smart grid becomes more widely deployed and deregulated because of three major independent factors:                Deregulation enabling the end user to choose between several utility providers service concurrent offerings from a single utility meter, possibly on the fly. In that scenario the utility meter will need to communicate upstream with several utility management centers or collector concentrators, thus basically multiplying the number of upstream messages by the number of utility providers.        The need to systematically enforce the utility meter security messaging and improve the internal utility meter security implementation to prevent cyber-terrorist smart grid attack risks as well as end user meter hacking fraud incentive. The highly sensitive utility meter cryptographic module therefore needs to operate as deeply as possible into the meter system design, typically down to the utility meter data and key registers, rather than at the communication network interface, thus requiring additional cryptographic protocols and messaging mechanisms in addition to the current standard specifications.        
The document US 2006/0271244 discloses an energy monitoring device including procedures for secure communication of data output from this device. The energy monitoring device includes a public/private key pair used to encrypt and/or digitally sign communications by the device. This allows the receivers of these communications to authenticate the communications to ensure that the device and/or communications have not been compromised. However, the using of the public/private key pair and/or digital signature is made according to a classical scheme which is nowadays well known by the person skilled in the art. Such a scheme does not optimize the communications exchanged between the energy monitoring device and the entity that bills for energy usage. This energy monitoring device is rather capable of communications via an ad-hoc “mesh” network for facilitating communications among devices which are substantially inaccessible due to either physical or economic limitations.
The document US 2011/0224935 relates to a measurement device, in particular energy counter for the safe detection and displaying of the count data and to a method for recognition of manipulations. It refers to the need that values that are taken and shown in the invoice should be beyond doubt for the consumer protection. These values are taken locally, are digitized and are transferred to a central office to be processed. The aim suggested by this document is to design a measurement device featuring data communication to at least one system in such a way that allows the system to identify the measurement data sent back as its own data, including a data manipulation check. To this end, the device has the capability of receiving signed and or encrypted measurement data, storing said measurement data in a memory in view for delivering back, and has the capability of offering time information related to a time reference.
The document US 2006/0206433 suggests that digital signatures are applied to metered energy data that is collected by a common data collection system. The system receives data from meters (each belonging to a certain customer) that may be owned by one or more utilities. The data sent by each meter is previously encrypted and signed. After receiving the data by the common data collection system, the data is stored by this system using public key cryptography to ensure that it is only accessible by the intended consumer of the data. When the data is transmitted to the intended consumer, it is digitally signed by the system to ensure the authenticity of the data as received by the consumer. The use of encryption and digital signatures allows the system to assure the integrity of the collected data even after the data has been communicated from the system (i.e., been published externally). However, to collect all the data metered by million of meters, the common data collection system has to be provided with huge data bases on the one hand, and these data bases must be connected to a very powerful data management system (computers) for quickly dealing the data in an efficient manner.
There is therefore a need for a communication system and method that further optimizes handling of data, in particular the upstream messages overload between a utility usage monitoring device (utility meter) and at least one utility management device or center.